Asymmetric aldol reactions are a useful method for synthesizing optically active β-hydroxycarbonyl compounds. Among these, optically active β-hydroxyaldehydes have particularly high importance as intermediates of medicine, agricultural chemicals, perfume and the like. However, because the well known asymmetric aldol reactions use an enolate or an enolate equivalent prepared from a ketone or carboxylic acid derivative, a multistep process via an optically active β-hydroxycarboxylic acid derivative has been required to obtain an optically active β-hydroxyaldehyde. In order to efficiently obtain an optically active β-hydroxyaldehyde by fewer processes, an asymmetric aldol reaction using an enolate derived from an aldehyde or an enolate equivalent such as enamine is preferred. In addition, in order to selectively carry out asymmetric cross-aldol reactions with different aldehydes, a technique to achieve control of one aldehyde as an enolate or an enolate equivalent and another aldehyde as an electrophile is required. As asymmetric catalysts to synthesize optically active β-hydroxyaldehydes by asymmetric cross-aldol reactions between different aldehydes, which have been known until now, only some organocatalysts are known.
Specifically, there are a technique using a proline catalyst by MacMillan et al. (Non Patent Documents 1 and 2), Barbas et al. (Non Patent Document 3), and Cordova et al. (Non Patent Document 4), a technique using an imidazolidinone catalyst by MacMillan et al. (Non Patent Document 5), a technique using a prolinol catalyst by Hayashi et al. (Non Patent Document 6), and Boeckman et al. (Non Patent Document 7), a technique using an axially chiral organocatalyst by Maruoka et al. (Non Patent Documents 8, 9 and 10), a technique using a histidine catalyst by Mahrwald et al. (Non Patent Document 11), and a technique using a diamine catalyst by Luo et al. (Non Patent Document 12) and the like. As a technique to achieve combinations of an electrophile aldehyde and a nucleophile aldehyde in asymmetric cross-aldol reactions as desired, a technique of Denmark et al. using an optically active Lewis base organocatalyst and a silyl enol ether derived from an aldehyde (Non Patent Documents 13, 14 and 15) is known.